(i) Field of the Invention
The present invention relates to an improvement in or relating to a hydaraulic master cylinder, and more particularly to an improved brake master cylinder for use in the hydraulic brake system for a vehicle which is specifically designed to detect a current volume of operating fluid accumulated in the reservoir by way of a float element.
(ii) Description of the Prior Art
It is generally known that the master cylinder in the hydraulic brake system of an automotive vehicle is constructed to detect a volutme of operating fluid in the fluid reservoir by using a float mechanism incorporated therein. More specifically, according to a typical construction of the conventional hydraulic brake system for use in an automotive vehicle, it is constructed as shown in FIG. 9 that as the level of operating fluid 2 in the interior of a fluid reservior 1 comes to be lower, a float 3 is adapted to follow downwardly to cause a switch 5 disposed at the bottom of the reservoir 1 to be turned on by using a magnet 4 mounted on the lower part of the float to have a warning lamp in the indicator of the vehicle not shown, for example, turned on so that a driver of the vehicle may be informed of the fact that the current quantity of the operating fluid 22 remaining in the fluid reservoir 1 is decreasing.
In this typical construction, it is seen that the fluid reservoir 1 is mounted through a mounting boss 6 onto a brake master cylinder body 7 in which there are incorporated many working pistons.
Further to the construction of the fluid reservoir assembly mounted upon the master cylinder in which the switch 5 is juxtaposed with respect to the mount boss 6 at the bottom of the fluid reservoir 1, it is generally constructed that a float element 3 disposed in a cooperative relationship with the location of the switch 5 is obliged to be positioned with its center line I offset rearwardly, or towards the direction of reverse operation of the vehicle on which the master cylinder is mounted, from the center line II of the fluid reservoir 1 by a distance l.
Since the master cylinder body 7 in the hydraulic brake system of a vehicle is generally known to those skilled in the art in connection with its construction and operation, any further description will then be omitted herein.
In the construction shown in FIG. 9, there are shown provided a cap for the fluid reservoir 1 designated at the reference numeral 8, passages for directing the operating fluid into the interior of the master cylinder body 7 designated at 9 and 10, and an operating rod at 11, respectively.
According to such a typical construction of the conventional master cylinder in the hydraulic brake system, when the vehicle having such a master cylinder reservoir construction is braked sharply in an emergency, it is observable that the operating fluid 2 in the inside of the fluid reservoir 1 would move forwardly or toward the direction of forward operation of the vehicle with the inertial force rendered therein, thus making the level of the fluid 2 turn from its initial horizontal plane 2a to an inclined plane 2b as shown schematically by dot lines in FIG. 9. Under such a condition, because of the general disposition of the float element 3 being offset rearwardly in the inside of the fluid reservoir 1, a current level of the operating fluid at the center line I of the float element 3 would then turn to be lower than the actual level thereof, accordingly. At this moment, the float element 3 will come lower to turn the switch 5 on, so that there will be produced an erroneous warning of shortage of fluid regardless of its actual due quantity, thus making the driver of the vehicle embarrassed uselessly.
In consideration of such a drawback particular to the conventional construction of a master cylinder reservoir in the hydraulic brake system of an automobile vehicle, it would be desirable to attain an efficient resolution therefor.
The present invention is essentially directed to the provision of a due and proper resolution to such a difficulty in practice as outlined above which has been left unattended with any proper countermeasures therefor.